Pxtmp and the like



the 11kt? and has partn-ular reterence to im- WILLIAM C. DOlVD, OF QUINCY, ILLINOIS.

OENTRIFUGAL PUMP AND THE LIKE.

Application filed April 24 1919.

To (Ill ur/tom it may com :I'It

Be it known that. .l Wuimmu (Ti Down, a citizen of the t nitcd States. residing at Quim-y. in the county of Adams and State of Illinois, have invented certain new and useful Improvements in (entrifugal lumps and the like, of which the following is a specification.

The present invention has to do with certain improvements in i -nrit'ugal pumps and proven'u. .I'it:-s in halanclng devices Ill arrangements for said pumps. When a ccnti'iiugal pump or the like is in op ration. there is created an end. thrust. on the impell r due to the difference in pressure hcta'ccn thc intake and discharge sides of tii'e impeller. This end thrust tends to shift the impeller and shaft lengthwise of the shaft in the hearings, and it must be either neutralized or fail anced in some manner. The use of me hanically balancing devices such as thrust hearings. etc, in some cases, is ulnlesirahle on lug to the cost of such hearings and to the 'lai-t that they occupy considerahle space and are subjected to wear and liable to get out of adjustment.

The main ohiect of the iuesent invention is to provide an automatic pressure operated halance for the roller or impeller so arranged that the balancing or neutralizing effect will at all times be exactly proportional to the difi erei'ice in pressure to he neutralizcd. That is to say as the difference in pressure between the intake and discharge sides changes, the balancing effect will simultaneously change so as to maintain the machine under proper balance at all times.

Another object of the invention is to so arrange the balancing device that it can he used a pump or machine of this type regardless ofxhe 3 mher of stages of increase of pressui Tl is to say, it can he used in conjunetain with single or multi-stago machines with equal advantage and satisfaction.

Other objects and uses of the invention will appear from' a detailed description oi.

the same which consists in features of construction and combinations of parts hereinafter described and claimed.

In the drawing:

The figure shows a longitudinal sectional view through a three-stagepump having applied to it the balancing device of the presout invention. Portions of this figure ar Specification of Letters Patent.

Patented Aug. :5. 1920,

Serial No 292.443.

shown in elevation for the purpose of simplifying the. drawing and an understanding of it. i

In the construction shown in the drawing,

there are provided low, intermediate and high pressure stages 1. and 3 respectively. The water or fluid inlet is shown at the point i and the discharge chamber at the point i The main shaft 13 is journalcd in the hearings i' and v in the usual manner, :1 lid s driven through a c upling 9 or in any ther nituhle manner. The stutiiug hoses m the lihe ill and it pro\ idc water seals at the points where the main shaft passes through the lug. 'llu'se stutliug boxes may hc of any suitable construction, and I will. therefore. not concern myself partied luii) ith a detailed description of them.

('ounected to and driven by the shaft 6 ar the low. intermediate and high pressure impellers 12, 13. and H. respectively, said impellers working in the low, intermediate and high pressure stages. respectively. The impeller 12 draws water from the low pressure chandler t and delivers it at increased pressure into the stage 1. The water of the stage i collects in the annular passage 15, and the impeller ill draws water from this passzure l5 and delivers it into the intermediate stage 2. 'l'his intermediate stage 2' communicates with an annular passage 16, and the impeller it draws water from the passage lti and deliwrs it to the high pressure stage Ii. Thence it is delivered from the pump.

It will he observed that there is an end thrust created and which must he taken up,

said cud thrust being equal to the overall i plied hy the effective area exposed to said pressure. This effective area is substantiall equal to the area of the openings of the impellers working in their respective cases. and is suhstantially equal to the area o Ehc cirrhdesignated by the numeral IT in the figure.

i will now describe in detail the particular halanciug device illustrated in the drawing in this case. The same includes a disk 18 mounted upon and secured to the shaft and having one face normall subjected to high pressurifluid. and the other face normally suhjected to low pressure fluid, so that the dill'crence in pressure on the two faces of this disk will at all times depend upon the as to overall difference in. pressure existing in the pump. By making the area of the disk of roper size the dili'ercnce in pressure operatin on the disk will bring about an exact ha ancing effect.

This result is secured by the provision of a fixed seat 19 adjacent to the high pressure stage, and another fixed seat 20 adjacent to the other side or face of the disk, there being a slight play permissible between the two faces just mentioned, so that in operation the shaft is allowed to shift endwise a very slight amount sufficient to uncover the seat 19 and'simultaneouslyto either coverth'e seat 20 or leave the same slightly uncovered. The bearing or-seat 20 is provided with one or more axial passages 21 communicating with a chamber 22, so that when the seat 20 is uncovered, water can flow thron h these passages and into the chamber 22. his chamber 22 in turn is in direct communication with the low pres- SHH' chamber} through a pipe or connection se that the pressure within the chamber 2).? is equal to that on the low pressure side of lhe pump.

it is believed that the operation of this balancing device will be readily understood from the foregoing description. 1 will state, however, that as soon as a difference in pressure is created, the disk 18 will be forced over a slight distance so as to uncover the seat 19, thereby permitting a slight flow of water past said seat, and this Water w ll find its way through the passages 22 and back to the low pressure side of the machine. It is to be observed that the area of the seat 19 should be slightly greater than the area to be balanced, so that when the d sk 15 is firmly up against the seat 19 the high pressure acting on one face of the disk 18 will slightly overbalancc the end thrust, thus forcing the disk and shaft a slight distance endwise even against the end thrust which istobe balanced. This slight movement will cease as seat 20 has been so nearly coverzd r i r 23 initially shut off the flow of water throng i the passe es 21 In practice will be found that when a pump embodying the features of the present P mp! invention is brought into operation, the

shaft with the impellers and balancing disk 18 will shift over a slight distance and will assume and maintain an intermediate position practically without variation during the operation of the machine. The amount of water which is allowed to leak back through the passage 21 and connection 23 is so slight that it may be practically ignored as far as the efficiency of operation of the machine is concerned.

It is to be observed that in the construc" tion shown in the drawing the seat constitutes in effect a valve which is closed in a more or less perfect manner by the end movement of the disk 18 and so as to either wholly or partially shut off the return of water to the low pressure side of the machine. Manifcstly any other convenient or suitable arrangement might be adopted fol; controlling this return 0 water, and, therefore, the seat 20 may be considered as constituting in effect a valve operable according to the position of the disk 18.

I claim:

In a machine of the class described the combination of amultistage centrifugal a shaft extendingthrough the same, a. plurality of impellers located on said shaft and working in tandem, an end balancing chamber surrounding said shaft, an axial passage connecting the last stage with said balancing chamber, a circular valve seat in the balancing chamber surrounding said passage, a balance disk on the shaft in the balancing chamber, a peripheral seat on said disk adapted to engage the valve seat aforesaid when the balancing disk is forced thereagainst, another axial passage leading from the opposite side of the balancing chamber to a point of discharge, a relatively small valve seat surrounding said passage and facing the balancing chamber, a relatively small disk on the shaft adjacent to said seat. and a peripheral seat on said relatively small disk adapted to engage the seat surrounding the discharge passage when the shaft moves in said direction, substantially as described.

WILLIAM G. DOWD. 

